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A100294
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Numbers of the form a^5 + b^4 with a, b > 0.
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10
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2, 17, 33, 48, 82, 113, 244, 257, 259, 288, 324, 499, 626, 657, 868, 1025, 1040, 1105, 1280, 1297, 1328, 1539, 1649, 2320, 2402, 2433, 2644, 3126, 3141, 3206, 3381, 3425, 3750, 4097, 4128, 4339, 4421, 5120, 5526, 6562, 6593, 6804, 7221, 7585, 7777, 7792
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OFFSET
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1,1
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COMMENTS
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In view of computing A300566, it would be interesting to have an efficient way to check whether a given (large) n is in this sequence. - M. F. Hasler, Apr 25 2018
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LINKS
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MATHEMATICA
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lst={}; Do[p=a^5+b^4; If[p<15000, AppendTo[lst, p]], {a, 16}, {b, 32}]; Union[lst]
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PROG
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(PARI) A100294_vec(L=10^6, k=4, m=5, S=List())={for(a=1, sqrtnint(L-1, m), for(b=1, sqrtnint(L-a^m, k), listput(S, a^m+b^k))); Set(S)} \\ all terms up to limit L. - M. F. Hasler, Apr 25 2018
(PARI) is(n, k=4, m=5)=for(a=1, sqrtnint(n-1, m), ispower(n-a^m, k) && return(a)) \\ Returns a > 0 if n is in the sequence, or 0 otherwise. - M. F. Hasler, Apr 25 2018
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CROSSREFS
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Cf. A100274 (primes of the form a^5 + b^4).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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